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Dead Battery

My battery keeps dying (it’s only 6 months old). If I jump start it everything is fine for that day.
However, I only drive the car once a month and when I come back it is kaput again. How long do you have to drive a car to fully recharge the battery?
How long can a battery sit idle?

My Lexus dealer can find nothing wrong with the battery or electrical system. The cars is 12 years old otherwise is perfect condition. 82,000 miles

Your best bet would be a Battery Tender trickle charger.

I have a 93 Caprice that gets driven occasionally (every 2 or 3 weeks). When it is driven, I put 40 to 60 miles on it for the day (no short trips). On top of that I use my Battery Tender once a month or so to top off the battery. The battery is ten years old and starts the car every time. I check the battery voltage and load test it on a regular basis, but I should replace it.

Depending on the alternator to charge a depleted battery puts a lot of stress on it. A Battery Tender is less expensive than a new battery or alternator.

Ed B.

Yes, you are a good candidate for a trickle charger. A modern car has a lot of live electrical systems even when it just sits around going nowhere. It is reasonable to assume a good battery can be drained in a month. A trickle charger should solve your problem.

I agree with the crowd. I’d expect a car to start after two or three weeks, but a month is pushing it.

If you have a power outlet that’s hot all of the time, it might be convenient to get a battery tender that plugs in there.

Make mine another vote of support for the trickle charger.

I had my battery go flat every week in my volvo. The battery was fairly new, it got charged up and then went flat again - drove me nuts. It turned out that after some very hot days (48C) here in Oz, the glovebox door/hatch had warped, so that when the hatch shut, the internal light (inside the glovebox) was still on. Once I realised (by listening to the ‘click’ of the switch), I added some padding to inside the hatch to ensure that when the glovebox door shut, the light went out - ta da!! no more flat batteries!!. And yes, the mechanic can measure these things too, by the way…:wink:

Your dealer should have been able to tell you that a car sitting for a month without being driven is a prime candidate for a dead battery. There are certain functions on the car (clock, ECM, security system, etc) that draw electrical current while the car is not being used.

My vote is for a battery tender.

Here’s what I use on lawn equipment and my motorcycle batteries during the winter and the battery is always fully charged when spring arrives. About the same thing as a Battery Tender, but at a fraction of the cost. I’ve owned several of them for 5+ years and they’re all still working. Just plug it in and leave indefinitely.